Society is burdened with an ever increasing amount of both organic and inorganic waste to dispose of in an economical yet safe means. The organic waste material, commonly referred to as refuse, may include a variety of materials such as leaves, saw dust, straw, livestock manure, garbage, and other waste materials which will decay and form compost under moist, aerobic conditions. Such compost material is often collected into windrows which are approximately 8 to 10 feet wide, 3 to 6 feet high, and several hundred feet long (windrows can be as long as desired) for the purpose of decomposing. During the composting process it becomes necessary from time to time to turn the contents of the windrow to allow fresher air to permeate into the composting material. A compost turner, such as the one shown in U.S. Pat. No. 3,369,797, is used to straddle a windrow and turn over the composting material. Machines of this type are well suited for turning a windrow, however, when material is dumped it may spill sideways and after the windrow has been turned several times, the composting material has a tendency to spread out so that the rotating drum of the compost turner does not extend as far as the windrow is wide. In addition, the outboard drive wheels of the compost turner, which are outboard of the rotating drum which turns the composting material, have a tendency to slip and lose traction on the composting material laying outside of the path of the rotating drum.